Ink jet recording apparatus for ejecting droplets of ink through promotion of capillary action

Abstract

A thermal ink jet recording apparatus includes a plurality of heating elements which serve as pressure generating members spaced apart from a plurality of nozzles. A reservoir, which stores ink prior to ejection through the nozzles, is formed between a nozzle plate and the pressure generating members and has a first cross-sectional area. A gap formed between a pair of substrates upon which the pressure generating members are disposed has a second cross-sectional area. An additional reservoir for storing ink is in fluid communication with the gap and has a third cross-sectional area. The first cross-sectional area is smaller than the second cross-sectional area and the second cross-sectional area is smaller than the third cross-sectional area for promoting capillary action in ejecting droplets of ink through the plurality of nozzles.

What is claimed is: 
     
       1. A method of ejecting droplets of ink from a plurality of nozzles of an ink jet recording apparatus, said apparatus including a nozzle plate having said plurality of nozzles, the method comprising the steps of: storing ink in second reservoir means having a third cross-sectional area;   supplying said ink to first reservoir means through a slit of a supporting member, said slit having a second cross-sectional area wherein, said second reservoir means being in fluid communication with said slit;   storing ink supplied through said slit in said first reservoir means, said first reservoir means having a first cross-sectional area; and   applying pressure to said ink stored in said first reservoir means for ejection of said droplets of ink through said plurality of nozzles;   wherein said first cross-sectional area is smaller than said second cross-sectional area and said second cross-sectional area is smaller than said third cross-sectional area for promoting capillary action in ejecting droplets of ink through said plurality of nozzles.   
     
     
       2. An ink jet recording apparatus for ejecting droplets of ink from a plurality of nozzles, comprising: a nozzle plate having said plurality of nozzles;   pressure generating means spaced apart from said plurality of nozzles;   first reservoir means for storing said ink, formed between said nozzle plate and said pressure generating means and having a first cross-sectional area;   support means for supporting said pressure generating means and having a slit for supplying said ink to said first reservoir means, said slit having a second cross-section area; and   second reservoir means for storing ink, in fluid communication with said slit and having a third cross-sectional area;   wherein said first cross-sectional area is smaller than said second cross-sectional area and said second cross-sectional area is smaller than said third cross-sectional area for promoting capillary action in ejecting droplets of ink through said plurality of nozzles.   
     
     
       3. The ink jet recording apparatus of claim 2, wherein said pressure generating means includes a plurality of substrates having front surfaces and back surfaces with a plurality of heating elements disposed in rows on the front surfaces. 
     
     
       4. The ink jet recording apparatus of claim 3, wherein said substrates are disposed parallel to the rows of heating elements with spaces therebetween. 
     
     
       5. The ink jet recording apparatus of claim 4, wherein said substrates are disposed parallel to the rows of heating elements with spaces therebetween. 
     
     
       6. The ink jet recording apparatus of claim 5, wherein the heating elements on adjacent substrates are provided vertically offset from each other. 
     
     
       7. The ink jet recording apparatus of claim 6, wherein said nozzle plate includes a nozzle portion having a uniform thickness and a step portion having a step from said nozzle portion, and wherein said first reservoir means is formed between the front surfaces of the substrates having the heating elements and said nozzle portion by said step. 
     
     
       8. The ink jet recording apparatus of claim 5, wherein said nozzle plate includes a nozzle portion having a uniform thickness and a step portion having a step from said nozzle portion, and wherein said first reservoir means is formed between the front surfaces of the substrates having the heating elements and said nozzle portion by said step. 
     
     
       9. The ink jet recording apparatus of claim 4, wherein the heating elements on adjacent substrates are provided vertically offset from each other. 
     
     
       10. The ink jet recording apparatus of claim 4, wherein said nozzle plate includes a nozzle portion having a uniform thickness and a step portion having a step from said nozzle portion, and wherein said first reservoir means is formed between the front surfaces of the substrates having the heating elements and said nozzle portion by said step. 
     
     
       11. The ink jet recording apparatus of claim 3, wherein the heating elements on adjacent substrates are provided vertically offset from each other. 
     
     
       12. The ink jet recording apparatus of claim 11, wherein said nozzle plate includes a nozzle portion having a uniform thickness and a step portion having a step form said nozzle portion, and wherein said first reservoir means is formed between the front surfaces of the substrates having the heating elements and said nozzle portion by said step. 
     
     
       13. The ink jet recording apparatus of claim 3, wherein said nozzle plate includes a nozzle portion having a uniform thickness and a step portion having a step from said nozzle portion, and wherein said first reservoir means is formed between the front surfaces of the substrates having the heating elements and said nozzle portion by said step. 
     
     
       14. The ink jet recording apparatus of claim 2, wherein the plurality of nozzles are disposed above the front surfaces of the substrates. 
     
     
       15. The ink jet recording apparatus of claim 14, wherein said nozzle plate includes a nozzle portion having a uniform thickness and a step portion having a step from said nozzle portion, and wherein said first reservoir means is formed between the front surfaces of the substrates having the heating elements and said nozzle portion by said step.